In the drilling and completion industries it is often desirable to affect tools or formations at a great distance from a surface located facility such as a rig, production facility, or wellhead. One example of an operation intended to affect a formation production is manipulation of a downhole choke to adjust flow rates from or into various zones or reservoirs segments. In order to perform such an operation, a choking mechanism can be actuated either hydraulically, electrically or the combination of these means. In the art, using these types of control generally require a number of control lines run from the surface through the wellhead related to changing the choke sizes at discrete locations in the wellbore. Such tools increase expense initially and generally create other issues to be overcome during well construction and completion operations. Where multiple choking locations are contemplated, generally control lines must pass through packers and other wellbore devices to allow a choking system be installed and administered correctly for it to work. Since choke adjustment happens infrequently the system of control lines is rarely used and only complicates well construction and completion operations.
Instead a far simpler system is contemplated where each valve has a unique profile for engagement by a shifting tool so that axial movement of the shifting tool will actuate a j-slot to rotate a pin extending from a sleeve that is in registry with a shaft having a reversing screw profile. Operation of the j-slot moves the pin in the track of the profiled shaft. The profiled shaft is constrained against rotation but is free to move axially in opposed direction. The choke valve member is tied to the translating profile shaft to allow the choke to move between fully open and fully closed and into positions in between. The profile shaft reverses direction at the fully open and fully closed positions of the choke to accomplish the closed, full open and part open positions that are in between.
Reversing screws are known and described in U.S. Pat. No. 4,998,576 in the context of a window mechanism. Typically the profile shaft is fixed against lateral movement and its rotation on its own axis drives a follower in opposed directions. The operation in the present invention is reversed in that a j-slot drives the follower along the profile on the profile shaft that is restrained against rotation so that rotational movement of what has traditionally been the follower in effect causes the profile shaft to move axially in opposed directions within a predetermined travel range.
A series of chokes accessible to a tool that engages unique profiles make it possible to balance flows from or into zones or to completely close off zones as desired. The system is economical as compared to systems that require control lines or power to drive motors at various locations. Other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined from the appended claims.